Optic nerve

Medically reviewed by Healthline Medical Team on February 2, 2015

The optic nerve is located in the back of the eye. It is also called the second cranial nerve or cranial nerve II. It is the second of several pairs of cranial nerves. The job of the optic nerve is to transfer visual information from the retina to the vision centers of the brain via electrical impulses.

The optic nerve is made of ganglionic cells or nerve cells. It consists of over one million nerve fibers. Our blind spot is caused by the absence of specialized photosensitive (light-sensitive) cells, or photoreceptors, in the part of the retina where the optic nerve exits the eye.

Glaucoma is one of the most common illnesses affecting the optic nerve. Glaucoma is caused by high intraocular pressure, or high pressure in the fluid that is inside the eye (vitreous fluid). This high pressure compresses the optic nerve and causes cells to die. It is referred to as atrophy of the optic nerve.

Although the optic nerve is part of the eye, it is considered part of the central nervous system.

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